splitting the difference cold/warm barrel question..

[69precision]

If you have a good barrel, there will be no statistical difference between the impact point of your first "cold bore" shot, and any of your warm or hot bore shots.

If there is, your barrel is junk or the shooter is the problem.

What about clean bore?

 

[Window]

I'm definitely not shooting big enough groups, I have never heard of shooting 30 round groups. I reckon a man is never too old to learn

Agreed. I shoot mostly barrel burners and by the time I would ever get to what they would say to be significant, I'd be screwing on a new barrel.

 

[HandgunHTR]

What about clean bore?

Clean bore is different. I shoot about 10 shots to foul before shooting groups.

 

[69precision]

Clean bore is different. I shoot about 10 shots to foul before shooting groups.

While I do notice a difference in cold vs hot, it is very subtle most times. I found clean vs dirty is where the difference lies. I think sometimes people mix those up, since they go to the range, come home, clean guns. Then next time they go the the range and the first shot is an inch high at 100, they think it's cold bore but really it's more the clean bore making that difference.

 

[gerpwaller]

I might be a little different in thinking. I have rifles set up for hunting and rifles set up for competition. My hunting rifles are set up for cold bore shot. You might only get one shot and that shot better be on the money. As far as my competition rifles, generally speaking, sometimes you get time to sight in and get get dope. But, by the time you are called for a particular stage, you may have a cold bore. that first shot hopefully is right on or it will be a long stage.

They do address getting statistically relevant data for hunting rifles in the podcast. That is also why I was doing a cold bore group for the proof barreled rifle in question. If you take the same rifle and do 5-10 x 3-5 round groups on different days you will get to a shot count that is statistically relevant and show the true first round or cold bore capabilities of the rifle. I'm my, albeit very limited, experience rifles that tend to group fairly regular 0.5 moa groups show to be legit 0.75-1 moa rifles when you do statistically valid group sizes. Rifles that tend to shoot 1 moa 3-5 round groups regularly tend to be legit 1.5-2 moa rifles if you do 20-30 round groups. That is whether you do cold bore groups or whether you are shooting strings (taking the barrel profile into account and what the theoretical capabilities of the rifle are). I would never expect a pencil barreled rifle to do more than 5 rounds without allowing the barrel to cool but a heavy target rifle should be relatively unaffected by shooting enough to get the barrel warmed up. Based on the hype and advertising around proof barrels they should fall into the category of the heavy target rifles and be able to handle longer strings of fire.

 

[cdennyb]

I see virtually no difference with my .300 win mag cold or warm. The barrel is warm when I hunt in middle of the day in Arizona first shot or tenth shot. It's cold in Idaho in the winter, 1st shot or last.

 

[blvette75]

How much difference on target is there between the cold bore shot and the rest of the group at 500 and 700 yards? If you're hunting at these distances the cold bore shot is the most important.

Is one shot really enough to consider the barrel warm? It's not on my rifles. I had a hunting rifle with a pencil barrel that would make considerable moves as it heated up. I took one shot about three hours apart to zero it.

I'd probably zero it at 200 yards and let the 100 yard rounds fall where they fall. Then I'd shoot it out to the maximum range (700 yards) in 50 or 100 yard increments and record the clicks required or reticle subtension to hit the bull at each yardage.

This and $1.75 will buy you a cup of coffee in some places.

A $1.75 for a cup of coffee jeez sounds like a deal.

 

[Mike Matteson]

If you have a good barrel, there will be no statistical difference between the impact point of your first "cold bore" shot, and any of your warm or hot bore shots.

If there is, your barrel is junk or the shooter is the problem.

where do you come up with this info?

 

[HandgunHTR]

where do you come up with this info?

About 40 years of shooting experience.

If you would like a bit more data, here you go. https://rokslide.com/forums/threads/cold-bore-zero-versus-very-hot-bore-zero-test.325335/

 

[Mike Matteson]

While I do notice a difference in cold vs hot, it is very subtle most times. I found clean vs dirty is where the difference lies. I think sometimes people mix those up, since they go to the range, come home, clean guns. Then next time they go the the range and the first shot is an inch high at 100, they think it's cold bore but really it's more the clean bore making that difference.

Interestng! I always put a fouling down the tube. 30 round groups are more for ES/ED info.

 

[Radman]

Kyoure of a long question but I feel the backstorry is important to understand it... My gun is zeroed at 100yrds. When my gun is cold bore/first shot it hits above the bullseye, and then all consecutive shots hit bullseye..(half inch difference from cold bore to warm bore) so I adjusted my zero to split the difference that way my cold bore shot hits top edge of bullseye and all consecutive/ warm bore shots hit bottom edge of bullseye, at 100yrd. This adjustment was 0.50 moa down. Whenever I'm shooting long range to confirm my dope I'm always shooting a "warm barrel" because I'll check my zero first, then I'll shoot 3 shot groups at different ranges (100-700yards). Never shooting a true cold bore at long range. Well my gun is primarily for hunting so the cold bore shot is what really counts.
That's why I think in theory bringing the zero down to split the bullseye would make sense that way at long range the the cold bore shot isn't too high but instead both cold bore and consecutive warm bore shots would be close to where you want to be hitting your target... The question is.. since I've never truly checked my dope with a cold barrel but only warm... by splitting the difference from cold bore and warm bore in theory my dope should stay the same? Bringing my cold bore long range shots just above to where my tested warm bore long range shots were? (yes I know the warm bore shots will now be a bit lower as well, but I'm trying to get best of both worlds in the event I need to take a follow up shot on an animal..)
Shooting a 147gr 6.5 creedmoor hornady eldm

 

[Radman]

JMO: If you're going to hunt zero the coldshot. If you're a target shooter zero the follow ups.

 

[CapeEsperance]

Check out the Hornady podcast episode 50 "Your groups are too small". It really brought to light somebody the inconsistencies I've seen shooting and changed the way I set up rifles.

eye opening podcast! I have to rethink my approach.